The subject matter disclosed herein relates to energy management, and more particularly to energy management effectuated by controlling temperature levels associated with a heating, ventilation and air conditioning (HVAC) system based on energy prices.
Many utilities are currently experiencing a shortage of electric generating capacity due to increasing consumer demand for electricity. Traditionally, utilities generally charge a flat rate, but with increasing cost of fuel prices and high energy usage at certain parts of the day, utilities have to buy more energy to supply customers during peak demand. Consequently, utilities are charging higher rates during peak demand. If peak demand can be lowered, then a potential huge cost savings can be achieved and the peak load that the utility has to accommodate is lessened. In order to reduce high peak power demand, many utilities have instituted time of use metering and rates which include higher rates for energy usage during on-peak times and lower rates for energy usage during off-peak times. As a result, consumers are provided with an incentive to use electricity at off-peak times rather than on-peak times.
Traditionally, to take advantage of the lower cost of electricity during off-peak times, a consumer typically manually operates an HVAC system during the off-peak times. For example, during off-peak times the consumer in cool mode can decrease the setpoint temperature of the HVAC system and during on-peak times the consumer can increase the setpoint temperature of the HVAC system and/or turn the HVAC system off. Control of the setpoint temperature is typically through a thermostat or a user interface/display associated with the thermostat. This user-managed approach is undesirable because the consumer may not always be present in the home to operate the system during off-peak hours. This is also undesirable because the consumer is required to manually track the current time to determine what hours are off-peak and on-peak.
One proposed third party solution is to provide an energy management system where a controller “switches” the actual energy supply to the HVAC system on and off. However, there is no active control beyond the mere on/off switching. There are also currently different methods used to determine when variable electricity-pricing schemes go into effect. Also, different electrical utility companies can use different methods of communicating periods of high electrical demand to their consumer, for example, phone lines, schedules, and wireless signals sent by the electrical utility company. Other electrical utility companies simply have rate schedules for different times of day.
Unfortunately, these existing energy management approaches require some unacceptable degree of user interaction and/or, when more fully automated, can result in undesirable temperature levels in the environment being managed.